Is there a better way to check and see if a certain value has already been inserted into a primary key field besides just doing a select * from .. where .. and seeing if it returns any rows before inserting the new record?

The only better way is to not have to check the primary key. If you use NOT NULL AUTO_INCREMENT then the primary key is automatically incremented every time you do an INSERT.
i.e.
CREATE TABLE sometable ( sid INTEGER NOT NULL AUTO_INCREMENT,
text1 VARCHAR(255),
text2 VARCHAR(255),
number1 INTEGER,
date1 DATE,
PRIMARY KEY (sid)
);
Then the key is automatically incremented when inserted into. i.e.